Following economic development and social evolution, the consumption and exploitation of natural resources is so aggressive that such consumption and exploitation is almost predatory. Natural resources are almost exhausted by human exploitation and large amount of natural resources are polluted during exploitation making the situation facing humanity extremely devastating. The level of human consumption of natural resources is rising higher and higher, as result, searching for new energy is a pressing issue facing humanity. Solar energy is a renewable energy source that is clean, environmentally friendly and virtually without limit. Sustainable development of economy favors solar energy, and among many different utilizations of solar energy, transforming solar energy into electricity is a major one. The technology of focusing solar power for photovoltaic power generation is to transform focused solar energy into electric energy.
Fixed photovoltaic module for solar power generation is the main stream form for solar power generation, in which photovoltaic modules are fixed on support mechanism, solar radiation is collected from sunrise to sunset, collected solar energy is transformed into electric energy, the amount of electric energy transformed is proportional to the effective radiation area of the photovoltaic module, while the effective radiation area is defined as the projection area on the surface of the photovoltaic module when the sun beam is perpendicular to the surface of the photovoltaic module. The earth's rotation causes the sun to rise and set every day, there is only a very short period of time when the sun beam is practically perpendicular to the surface of the photovoltaic module, when the sun beam is tilted, the effective radiation area is the full surface area of the photovoltaic module times cosine of the angle between the surface of the photovoltaic module and the sun beam, as a result, the solar energy collection efficiency is relatively low, large amount of solar radiation is wasted.
In order to resolve above problems, azimuth driving device is utilized to achieve sun-tracking by controlling the azimuth of the photovoltaic module, in which the photovoltaic module tracks trajectory of the sun to maximize the amount of time when the sun beam is perpendicular to the surface of the photovoltaic module, so that solar transform efficiency is maximized. In current market, bearing turntable is widely used as the driving device to control azimuth motion, in which the bearing turntable holds photovoltaic module on the support mechanism, sun-tracking is achieved through controlling the bearing turntable that holds photovoltaic module. A problem with such bearing turntable is its lack of protection against wind overload, strong wind causes harmful incoming an impact load on the bearing turntable, and such harmful incoming impact load damages bearing turntable and reduces the service life of the sun-tracking device. In addition, after a period of time in deployment, wearing between moving components of the bearing turntable creates gaps between components, such gaps can only be fixed manually by skilled workers, as a result, the maintenance cost for such large scale sun-tracking system is very high which prevents large scale commercial deployment.